Rediff.com India — Rediffmail account is compromised

Hi there, My rediffmail account has been hacked and the security question, alternate mail id and the phone number has been changed as well. I did not use that email for a while and now wanted to use it to sign into one of my related accounts with another platform. II am really worried about the sensitive information that could have been misused by the hacker. kindly help to retrieve it for me. you can contact me on [protected]@gmail.com for the followup and progress in regards to this issue. I would like the company to take a serious action on the hacker.
thanks